Occurrence of Hydroclathrus clathratus in northern New Zealand waters

Hydroclathrus clathratus (C. Agardh) Howe (Phacophyta: Punctariales) is recorded from two harbours on the Northland east coast, North Island, New Zealand. The possibility of its being a recently introduced species is discussed.     

Seasonal hydrology of Port Fitzroy,Great Barrier Island,New Zealand

At 2‐monthly intervals between March 1974 and January 1975 seawater temperature and salinity (at 0 m and 5 m depths) and turbidity (as Secchi disc visibility) were measured in Port Fitzroy and adjacent bays on Great Barrier Island (36°11'S, 175°21'E). A seasonal pattern was evident in all three parameters. Variation between depths and between high and low tides was generally only slight, although differences of up to 3.6°c and 12.58‰ were recorded occasionally. Maximum temperatures (22–23°c) occurred in January, with minima (13–14°c) in July. Salinities were generally between 35.0 and 35.6‰, but values as low as 22.25‰ at the surface were recorded after heavy rainfall. Secehi disc visibility measurements of turbidity varied between 2.0 and 12.5 m, but were usually 5–9 m.

A graded series of four generalised areas was distinguished, ranging from sheltered, almost estuarine inner bays, to exposed open water with properties similar to outer Hauraki Gulf water.

The circulation through Port Fitzroy comprises the main exchange of water through the northern entrance channel, causing a southerly movement of water on the flood tide and a northerly movement on the ebb, together with a small compensatory exchange through the narrow southern entrance.     

Fecundity in the marine spiny lobster Jasus verreauxi (H. Milne Edwards) (Crustacea: Decapoda: Palinuridae)

Fecundity in Jasus verreauxi (H. Milne Edwards, 1851) has been studied by a detailed investigation of (a) the total weight of eggs carried by female specimens, (b) the average number of eggs per 1 g sample, and (c) the total number of eggs carried by females. In mid October 1966, 217 females “in berry” (that is, carrying external eggs) were examined and measured at Spirits Bay, New Zealand. The fecundity study is based on the results obtained from 21 selected specimens, with carapace lengths from 15.5 cm to 23.5 cm.

A direct relation was found between the total weight of eggs carried and increase in carapace length. The total weight of eggs carried varied from about 51 g to 238 g for carapace lengths of 15.5 cm to 23.5 cm. No correlation was shown between the average number of eggs per 1 g sample and increase in carapace length. Considerable variation was noted in the number of eggs per 1 g sample, which ranged from a low count of 6,453 eggs to a high count of 8,341 eggs. The total number of eggs carried by female J. verreauxi was found to be related to an increase in carapace length. Furthermore, increase in fecundity per relative carapace length increase was noted to be greater in smaller specimens than in larger specimens. The total number of eggs carried ranged from about 385,000 for a carapace length of 15.5 cm to 1,940,000 for a carapace length of 23.5 cm.

Fecundity, as measured by the total weight of eggs carried and the total number of eggs produced, was found to be much higher in J. verreauxi than in several Jasus species previously studied by other workers.     

Fecundity of chinook salmon (Oncorhynchus tshawytscha) from the Waitaki and Rakaia Rivers,New Zealand

The fecundity of chinook salmon (Oncorhynchus tshawytscha) was estimated from maturing fish captured by anglers in the lower Waitaki River in 1985 and 1987–89, and from mature fish spawned at the Glenariffe Research Station on the Rakaia River in 1992. Fecundity was positively correlated with fork length (FL); estimated fecundities at 750 mm FL were 5024 eggs for Waitaki and 4829 eggs for Glenariffe salmon. The slopes of the regressions of fecundity on FL differed between the populations but the Glenariffe data did not differ from Rakaia River samples from 1967, 1973, and 1976. Significant inter‐annual variation in the FL‐fecundity relationship was detected in Waitaki River samples. Egg weights, taken from the Glenariffe samples, were positively correlated with length and averaged 0.17 g. However, salmon with high fecundity for their FL tended to have small eggs, and vice versa.     

丹麦钢头鳟染色体核型分析

为了了解引进品种的种质遗传特征,作者采用PHA体内直接注射法制备了丹麦钢头鳟(Oncorhynchus mykiss)的染色体,并进行其核型分析。结果表明,与虹鳟(O.mykiss)略有不同,钢头鳟的染色体数目为58条,核型公式为2n=44m+14t,臂数NF=102。丹麦钢头鳟染色体核型结果为其养殖、良种选育或者杂交育种等的研究和应用提供了种质资源基础数据。     

虹鳟(Oncorhynchus mykiss)维生素D受体a(VDR-a)基因克隆以及网箱养殖密度对其表达和血液中Ca2+含量的影响

本文从虹鳟(Oncorhynchus mykiss)肾脏组织中克隆得到维生素D受体a(VDR-a)基因的全长cDNA序列。结果表明, 虹鳟VDR-a的cDNA全长为2606bp, 共编码797个氨基酸, 主要包括A/B区、C区、D区以及E/F区。实时定量PCR分析表明, 高密度网箱养殖使得虹鳟肾脏和肝脏中VDR-amRNA的表达降低, 并且随着养殖时间延长和养殖密度的增加VDR-amRNA的表达减少更加显著; 血液中Ca2+含量随着养殖密度的升高而降低, 养殖密度升高使得Ca2+的主动运输过程减弱, 因此高密度养殖能导致产生低浓度Ca 2+, 这样对应的VDR-amRNA的表达也降低。说明养殖时间对VDR-amRNA表达的影响是通过养殖密度的变化来实现的。     

Low levels of aluminium causing death of brown trout (salmo trutta fario,L.) in a Swiss alpine lake

Several attempts to stock fish in acidified alpine lakes have so far proven unsuccessful. In an effort to investigate the problems associated with the stocking of fish, the Swiss alpine Lake Laiozza was chosen for experimentation. An analysis of Lake Laiozza water revealed low ion concentrations (0.5 mg Ca/L, 0.13 mg Na/L, 0.02 mg Cl/L), moderate aluminium concentrations (121 ± 28 µg Al/L), and a moderately low pH (5.41 ± 0.21). As in common practice, one and two year old brown trout were exposed in a closed keep-net in Lake Laiozza. The water of Lake Laiozza proved to be acutely toxic to the fish. Mucous clogging of the gills, gill epithelial damage, plasma electrolyte losses, and high hematocrits were the predominant symptoms observed. All symptoms observed are typical for an acute intoxication with aluminium. This stands in contrast to the generally accepted view that aluminium concentrations lower than 200 µg Al/L should not be toxic to brown trout at a pH 5.4. The low Na and Cl and low Ca concentrations in the Lake Laiozza water seem to have rendered the fish much more susceptible to aluminium intoxication.     

Tropical high Andes lakes: A limnological survey and an assessment of exotic rainbow trout (Oncorhynchus mykiss)

Tropical high Andes lakes are aquatic ecosystems with peculiar limnological characteristics that are related to their geographical location and high altitude, yet they remained understudied. We present the results of a standardized survey of morphometric, physico-chemical and biotic variables in 32 high altitude lakes of the Cordillera del Tunari (Eastern Andes of Bolivia). Based on the variables measured, we identified three lake types. One group of lakes differed from the other lakes by a relatively high pH and biological productivity (as evidenced from higher densities of phytoplankton, zooplankton, and fish). A second group of lakes consisted of relatively large and deep water bodies with neutral to slightly acid pH and with a relatively high occurrence of the large cladoceran Daphnia pulex. The third group contained relatively small, shallow, and acid lakes with no Daphnia. Rainbow trout occurred in more than half of the lakes and catch yields were very variable. Overall, the abundances of different organism groups tended to be positively associated (e.g. phytoplankton, copepods, rotifers, fish) indicating the existence of a major productivity gradient. We found no negative associations between trout catches and densities of any of the major zooplankton groups, suggesting moderate to low top-down effects of trout on the zooplankton communities.     

复方中草药对虹鳟免疫保护力的影响

【目的】研究复方中草药对虹鳟(Oncorhynchus mykiss)肝脏免疫功能及肠道免疫相关基因的影响。【方法】将红枣提取物、山药提取物和黄芪提取物按照质量比1∶1∶1混合,分别按质量分数0(对照)、0.3%、0.6%和1.2%添加到虹鳟基础饲料中,饲喂体长7.6~8.9 cm的虹鳟幼鱼56 d。用副溶血弧菌(Vibrio parahemolyticus)对幼鱼进行攻毒试验(5.48×10⁶ cfu/尾),4 d后,取其肝脏和肠道,测定肝脏的生理生化指标,用半定量PCR及荧光定量PCR测定肠道免疫相关基因的表达。【结果】与对照组比较,肝脏的总抗氧化能力(T-AOC)显著升高(P<0.05),溶菌酶(LZM)水平极显著升高(P<0.01),酸性磷酸酶(ACP)、过氧化氢酶(CAT)活性显著降低(P<0.05),碱性磷酸酶(ALP)活性极显著降低(P<0.01),0.6%剂量组的丙二醛(MDA)极显著降低(P<0.01),而SOD无显著差异(P>0.05);各复方中草药组肠道的肿瘤坏死因子(TNF-α)及1.2%剂量组转化生长因子-β(TGF-β)转录水平极显著降低(P<0.01),0.3%和0.6%剂量组的补体3(C3)转录水平显著升高(P<0.05)。【结论】复方中草药(红枣+山药+黄芪)可提高感染副溶血弧菌的虹鳟非特异性免疫功能。